Understanding the structures and aromaticity of heteroporphyrins with computations

Abstract

Different heteroporphyrins go through two different aromatic pathways, either 18π-[18]annulene or 22π-electron model.

Synthesis and Characterization of N-Methylporphyrins, Heteroporphyrins, Carbaporphyrins, and Related Systems

“…In the latter category, substantial efforts have been put into the application of porphyrins as photosensitizers in photodynamic therapy (PDT) . Modifications to the porphyrin framework allows beneficial features to be enhanced and also enables fundamental issues to be addressed such as the origin of aromatic character in porphyrinoid systems. , In this rapidly developing field, porphyrin-type systems have been modified by ring expansions or contractions, by ring fusion to form extended structures, by core modification, , and so on. Although less studied, alkylation of the porphyrin core also induces significant changes in the porphyrin chromophore .…”

The origin of experimental regioselectivity in ring-closing reaction of pyrido[1,2-e]purine systems and comparison of the aromaticity character of probable products: a mechanistic study based on DFT insights

“…49 The index has been applied to various organic and inorganic systems. [65][66][67] In the ACID method, the ring current is illustrated in the presence of an applied magnetic field by an ACID isosurface at a specific value of the ACID function (isovalue). Thus, clockwise and counterclockwise ring current flows are directly determined by aromatic and antiaromatic characters, respectively.…”

First Sublimation Thermodynamics and First Gas‐Phase Experimental Molecular Structure of Heteroporphyrins: 5,10,15,20‐Tetraphenyl‐21‐X, 23‐Y‐Porphyrins (X=O or S; Y=N or S)

“…The first gas‐phase experimental molecular structure of heteroporphyrins was studied and geometric and vibrational parameters for HSPP were derived by using synchronous gas‐phase electron diffraction and mass spectrometric (GED/MS) experiments. More extended than in [10] theoretical DFT calculations for neutral species of HOPP , HSPP and S 2 PP were performed. Moreover, in order to correlate the trends in the measured sublimation enthalpies an arrangement of dimeric associates of these heteroporphyrins were simulated by theoretical calculations with BSSE corrections taken into account.…”

“…[9] The macrocycle distortion due to the presence of large heteroatom-containing groups (PH, AsH, SiH 2 , O, S, etc.) and aromaticity of heteroporphyrins were discussed recently [10] on the base of QC calculations at B3LYP/6-31G(d) level.…”